Hydroxyl functional monomers, their preparation and their use in preparing polyurethanes

Abstract

 By reacting polyamines with ethylene carbonate, hydroxyethyl urethane diols and polyols are produced. These diols and polyols are particularly useful for the synthesis of polyurethanes by reaction with diisocyanates or polyisocyanates.

Description

[0001] This invention relates to the formation of hydroxyl functional monomers in general, and in particular to the formation of hydroxyl functional monomers useful in the synthesis of polyurethanes.

[0002] Synthesis of polyurethanes by reacting isocyanates and alcohols is well known to the art. Typically, long or medium chain diols or polyols are used to provide the "soft" segments of segmented polyurethanes. These polyols generally consist of hydroxyl terminated polyethers or polyesters. Reaction of these polyols with polyisocyanates produces polyether or polyester urethanes, respectively. Short chain polyols are often reacted with polyisocyanates to form the "hard" segments of segmented polyurethanes.

[0003] Unfortunately, commercial availability of polyols appropriate for use in the synthesis of polyurethanes is somewhat limited. However, certain polyamines having backbones appropriate for polymer synthesis are more readily available. They may be reacted with polyisocyanates, to form polyureas. However, reactions between polyamines and polyisocyanates are often too fast to allow for commercially feasible production. Moreover, polyureas generally have limited thermal processability.

SUMMARY OF THE INVENTION

[0004] The present invention provides a process of producing novel hydroxyethyl urethane polyols, which term herein includes diols, from readily available polyamines, including diamines. In our process, a compound A_n-M, in which M represents a desired moiety, A represents a primary or secondary amine group and n is a number greater than or equal to 2, is reacted with a cyclic e.g. ethylene carbonate to produce the desired polyols. These polyols are then readily and controllably reacted with polyisocyanates, including diisocyanates to produce novel polyurethanes. Ether and ester free polyols according to the present invention are believed to have great potential in the preparation of polyurethanes for use in biomedical applications. Such polyurethanes and their preparation are described in detail in our copending patent application No.      , entitled "BIOSTABLE SEGMENTED ALIPHATIC POLYURETHANES AND PROCESSES FOR THEIR PREPARATION".

DESCRIPTION OF THE INVENTION

[0005] In some applications requiring elastoplastic poly­urethanes, inclusion of a dimer acid backbone in the "soft" segments of segmented polyurethanes has been found particularly desirable. The dimer acids as the term is used herein are described and discussed in the book "The Dimer Acids", edited by Edward C. Leonard, published by Humko Sheffield Chemical, 1975. Dimer acids are the reaction product of a Diels-Alder addition or other coupling process of two aliphatic, unsaturated, predominantly 18 carbon fatty acids. Dimer acids take the form of single ring, double ring or branched chain structures predominantly having two carboxylic acid functionalities.

[0006] Dimer acid based products commercially available include dimer isocyanate, dimer amine, and dimerol. All three are produced beginning with dimer acid, and include the 36 carbon dimer acid backbone. Representing the 36 carbon dimer acid backbone as "D", the formula for dimerol is HO-D-OH, the formula for dimer isocyanate is OCN-D-NCO, and the formula for dimer amine is H₂N-D-NH₂. While dimerol may be reacted with diisocyanates to produce polyurethanes, dimer amine is presently more readily obtainable.

[0007] Dimer acids and derivatives thereof are available from Humko Sheffield Chemical Operation of Kraftco Corporation, U.S.A. Whilst there is some variability in the nature of the preparations available, it is well within the scope of a man skilled in the art to establish the suitability of - particularly preparation for his purposes using simple experimentation.

[0008] Other polyamines are A_n-M are also appropriate for use in the claimed invention. These include primary and secondary polyamines with hydrocarbon backbones, such as hexamethylene diamine, piperazine, 1,4-diaminobutane, xylylene diamines, 4,4-diaminodicyclohexylmethane, isophorone diamine, 1,3-diaminopropane and similar compounds. In addition, by suitable choice of polyamine, the invention alllows for inclusion of a variety of polymer backbones in polyurethanes, especially segmented polyurethanes. Examples of such amines A_n-M include polydimethyl siloxane (PDMS), a silicone polymer available from Petrarch Systems with aminopropyl termination (PDMS diamine) and polyoxypropylene diamines. Other amino terminated polymeric materials based on polyethers, polycarbonates, polyamides and polyesters also have potential use in the present invention. Shorter chain polyamines which include ether, ester, or carbonate functional groups may also be used. The present invention allows any desired polyamine which is free of ethylene carbonate-reactive functional groups (other than amines) to be converted to urethane polyols of the invention, and then to be incorporated in polyurethanes. The polyols produced may be reacted with one or more polyisocyanates, including diisocyanates, to produce the polyurethanes.

[0009] The following non-binding Examples help illustrate the invention. Long chain diamines and the diols produced therefrom are particularly useful in fabricating the 'soft" segments of segmented polyurethanes. Examples 1-4 and 9-10 are illustrative.of this aspect. Short chain diamines and the diols produced therefrom are useful in producing the "hard" segments of segmented polyurethanes. Examples 4-7 are illustrative of this aspect.

Example 1

[0010] 268.2 grams (1.00 eq.) of dimer amine and 89.0 grams (1.01 eq.) of ethylene carbonate (converted to a liquid by warming) were weighed into a nitrogen purged jar. A magnetic stirring bar was placed in the jar and it was covered. The mixture was warmed with stirring on a magnetic hot plate. The mixture cleared within 30 minutes and its viscosity rose. The mixture was stirred a total of 3 hours while the temperature was maintained between 70-90°C. Infrared spectroscopy indicated that the carbonate absorption (1800cm⁻¹) had disappeared while being replaced by the expected urethane carbonyl peak (1700cm⁻¹).

[0011] The product of Example 1, bis-hydroxyethyl dimer urethane (hereafter BHEDU diol) is useful in the preparation of a variety of polymers. The formula for BHEDU diol is HO-CH₂-CH₂-OOC-NH-D-NH-COO-CH₂-CH₂-OH, in which "D" represents the hydrocarbon backbone of dimer acid. In particular, it is useful in production of ether and ester free polyurethanes as disclosed in our above-mentioned co-pending application of even date herewith No.      . One example of a polyurethane produced employing the of Example 1 is set forth in Example 2, below.

Example 2

[0012] 29.1 grams (.10 Eq.) of dimer diisocyanate were mixed with 7.4 grams (.125 Eq.) of 1,6-hexane diol and 8.9 grams (.025 Eq.) of BHEDU diol. The covered mixture was placed into a 121°C (250°F) oven until the solid 1,6-hexane diol melted. At that point, the mixture was removed from the oven and stirred for 10 minutes, and a drop of dibutyltin dilaurate was added to catalyze the reaction. The mixture was stirred until thickening indicated that the reaction was well underway. The covered mixture was returned to a 121°C (250°F) oven for 3 hours. After removing the mixture from the oven, 20.0 grams (.15 Eq.) of 4,4-diisocyanatodicyclohexlmethane (Desmodur-W®, produced by Mobay, Inc.) and 4.5 grams (.10 Eq.) of 1,4-butane diol were added to the mixture and stirred. The covered mixture was returned to the 121°C (250°F) oven for 2 minutes, and removed and stirred until thickening indicated that polymerization was well underway. The covered mixture was returned to the oven overnight to complete the cure.

[0013] The resultant product is a solid elastoplastic polyurethane having an ultimate tensile strength of 3710 p.s.i., 100% secant modulus of 1613 p.s.i., 388% elongation at break and Shore hardness of 88A. The polyurethane produced is believed useful as an insulator for implantable electrical leads and/or as a coating or other functional portion of an implantable medical device.

[0014] The general method disclosed in Example 1 is also applicable to other polyamines to produce polyols including diols appropriate for use in production of polyurethanes and other polymers. Examples 3, 5, 7 and 9 disclose other urethane diols fabricated from a variety of primary and secondary diamines, to indicate the general applicability of the method to produce urethane polyols. Examples 4, 6, 8 and 10 demonstrate use of the urethane diols produced to produce polyurethanes.

Example 3

[0015] 403 grams (.300 Eq.) of aminopropyl terminated polydimethylsiloxane (Petrarch Systems) and 26.64 grams (.303 Eq.) of ethylene carbonate were combined in a reaction vessel previously dried with a purge of nitrogen. The ethylene carbonate was added first, then the diprimary amine. The mixture was initially incompatible. The mixture was stirred and heated on a magnetic hot plate at ambient temperature. The temperature was gradually increased from 40°C to 105°C over the first hour of heating and stirring. The temperature was gradually reduced to 60°C over the next hour, and the heating element was turned off after 2 hours of stirring. The mixture was stirred for an additional 3 hours at room temperature. Infrared spectroscopy performed on samples of the resultant liquid indicated that the expected reaction had taken place to produce a urethane diol. PDMS diamine has the general formula H₂N-(CH₂)₃-PDMS-(CH₂)₃-NH₂. The formula for the resultant diol (PDMS urethane diol) is HO-CH₂-CH₂-OOC-NH-(CH₂)₃-PDMS-(CH₂)₃-NH-COO-­CH₂-CH₂-OH in which "PDMS" represents polydimethyl­siloxane.

Example 4

[0016] 5.7 grams (.004 Eq.) of the PDMS urethane diol prepared according to Example 3 were added to 28.62 grams (.196 Eq.) of 9-hydroxymethyl octadecanol and 26.6 grams (.200 Eq.) of 4,4-diisocyanatodicyclohexylmethane (Desmodur-W®, produced by Mobay, Inc.). The reactants were mixed together in a beaker, and stirred. The mixture was then placed into a 121°C (250°F) vacuum oven for 10 minutes. The mixture was then removed, stirred for an additional 10 minutes and replaced in the oven for an additional 15 minutes. The mixture was then removed, stirred for 5 minutes and catalyzed with 1 drop of dibutyltin dilaurate. The mixture was stirred until thickening of the mixture made further stirring impossible. The mixture was placed back in the oven overnight to complete the cure. Samples of the material were compression molded at 215.6°C (420°F). The resulting polyurethane had ultimate tensile strength of 3370 p.s.i., yield strength 2960 p.s.i. at 7% elongation and 215% elongation at break. The polyurethane is a solid elastoplastic believed useful either as a coating, sheet or molded plastic.

Example 5

[0017] 86.14 grams (2.00 Eq.) of piperazine, manufactured by Aldrich Chemical Co. were combined with 184.8 grams (2.1 Eq.) of ethylene carbonate in a round bottom flask. The reactants were melted and mixed under magnetic stirring. The exothermic reaction elevated the temperature of the mixture to about 140°C, with temperature falling off after about 10 minutes. The mixture was thereafter heated to maintain a temperature of 100°C. After 18 hours, IR spectra were taken, indicating the expected conversion to a urethane diol. The resulting product is an amber liquid at 100°C, and is solid at room temperature. The structural formula for the urethane diol is:

Example 6

[0018] 74.46 grams (.51 Eq.) of the urethane diol produced in Example 5 were combined with 148.73 grams (.50 Eq.) of dimer isocyanate, and stirred until homogenous. The mixture was placed in a 121°C (250°F) oven, and allowed to react overnight. The resulting polyurethane was a solid polymer having an ultimate tensile strength of 1738 p.s.i., a 100% secant modulus of elasticity of 934 p.s.i. and 360% elongation at break. The resulting ether and ester free polyurethane is believed usable as a coating or an adhesive.

Example 7

[0019] 116.00 grams (2.0 Eq.) of hexane-1,6-diamine were combined with 184.80 grams (2.10 Eq.) of ethylene carbonate in a 1 liter round bottom flask. The reactants were heated until melted and mixed by magnetic stirring. The reaction was strongly exothermic, causing the temperature of the mixture to rise to 170°C, boiling some ethylene carbonate off. After 18 hours, IR spectra were taken, indicating conversion of the diamine to a urethane diol. The urethane diol is a red-brown solid at room temperature. The formula of the urethane diol is HO-CH₂-CH₂-OOC-NH-(CH₂)₆-NH-COO-CH₂-CH₂-OH.

Example 8

[0020] 148.73 grams (.50 Eq.) of dimer isocyanate were combined with 66.81 grams (.51 Eq.) of the urethane diol produced in Example 7, heated to 121°C (250°F) and mixed in order to produce a homogenous mixture. The mixture was allowed to react overnight at 121°C (250°F). The resulting product was a solid polymer having ultimate tensile strength of 1079 p.s.i., 100% secant modulus of elasticity of 328 p.s.i. and 656% elongation at break. This polyurethane is believed useful as an adhesive.

Example 9

[0021] 156.5 grams (.5 Eq.) of Jeffamine ED 600, a polyalkyl ether diamine produced by Texaco were added to 44.9 grams (.51 Eq.) of ethylene carbonate in a 500 mm flask under magnetic stirring sufficient to produce a vortex. The mixture was heated to 50°C and maintained at that temperature over night to produce a polyalkyl ether urethane diol (Jeffamine methane diol). Jeffamine urethane diol is liquid at room temperature, and is believed to have the basic formula:

Example 10

[0022] The diol produced in Example 9 above was dried over night at 100°C under 30 mm Hg vacuum prior to use. 100.25 grams (.25 Eq.) of the heated, dried diol were measured into a polypropylene beaker in a nitrogen purged dry box. 20.75 grams (.25 Eq.) of cyclohexane diisocyanate were added to the diol, and the mixture was stirred until the cyclohexane diisocyanate was melted and the mixture was homogeneous. The homogeneous mixture was placed in a 125°C oven under nitrogen purge to final cure. The product was a polyether urethane having an ultimate tensile strength of 1398 p.s.i., a 100% secant modulus of elasticity of 315 p.s.i., and 356% elongation at break.

[0023] The previous examples illustrate both the synthesis of urethane polyols and their use in synthesis of polyurethanes. The examples are intended to illustrate the claimed invention, and should not be construed as limiting the scope of the invention.

Claims

1. A process for the preparation of a polyurethane which includes a desired moiety M, which comprises
selecting a compound A_n-M wherein M represents the desired moiety, A represents a primary or secondary amine group and n is a number greater than or equal to 2,
reacting said compound with a cyclic carbonate to produce the desired urethane polyol,
and reacting said polyol with one or more diisocyanates or polyisocyanates.

2. A process as claimed in claim 1 wherein in the compound A_n-M, n represents 2 and a urethane diol is formed before polyurethane formation.

3. A process as claimed in claim 1 or claim 2 wherein in the compound A_n-M, M represents a desired hydro­carbon moiety.

4. A process as claimed in any ofclaims 1 to 3 wherein the cyclic carbonate is ethylene carbonate.

5. Urethane polyols, having the general formula (HO-CH₂-CH₂-OOC-NX)_n-M, wherein M represents a hydrocarbon moiety, N represents a primary or secondary amine group, n is a number equal to or greater than 2, and X represents a hydrogen or a hydrocarbon moiety.

6. Urethane polyols having the general formula (HO-CH₂-CH₂-OOC-NX)_n-M, wherein M represents the polymer backbone of a polymer selected from the group including polysiloxanes, polyesters, polyethers, polyamides and polycarbonates, N represents a primary or secondary amine group, n represents a number equal to or greater than 2, and X represents a hydrogen, hydrocarbon, polysiloxane, polyester, polyether, polyamide or polycarbonate moiety.

7. A urethane diol having the formula:
HO-CH₂-CH₂-OOC-NH-D-NH-COO-CH₂-CH₂-OH, wherein D represents the hydrocarbon backbone of dimer acid.

8. A urethane diol having the formula: HO-CH₂-CH₂-OOC-NH-(CH₂)₃-(PDMS)-(CH₂)₃-NH-COO-­CH₂-CH₂-OH, in which PDMS represents polydimethylsiloxane.

9. A urethane diol having the formula: HO-CH₂-CH₂-OOC-NH-(CH₂)₆-NH-COO-CH₂-CH₂-OH.

10. A urethane diol having the formula:

11. A urethane diol having the formula:
HO-CH₂-CH₂-OOC-N-R-N-COO-CH₂-CH₂-OH,
wherein R represents a polyalkyl ether backbone.

12. A process for preparing a polyurethane as claimed in any of claims 1 to 3 wherein the urethane polyol produced is a urethane polyol as claimed in any one of claims 5 to 11 which is then reacted with one or more diisocyanates or polyisocyanates.

13. A process for preparing a polyurethane wherein a urethane polyol as claimed in any one of claims of claims 5 to 11 is reacted with one or more diisocyanates or polyisocyanates.

14. A process for preparing a segmented polyurethane which includes the hydrocarbon of dimer acid which comprises reacting dimer amine with ethylene carbonate to produce a urethane diol, and reacting said diol with one or more diisocyanates or polyisocyanates.

15. A method of producing a segmented polyurethane which includes a polyether backbone, comprising the steps of reacting an amino terminated polyether with ethylene carbonate to produce a polyether urethane polyol; and
reacting the urethane polyol produced in the previous step with one or more diisocyanates or polyisocyanates to produce a polyether urethane.

16. A method of producing a polyurethane which incorporates a polydimethylsiloxane backbone, comprising the steps of:
reacting amino terminated polydimethylsiloxane with ethylene carbonate to produce a urethane diol; and
reacting the urethane diol produced in the previous step with one or more diisocyanates or polyisocyanates to produce a polyurethane.

17. A process for the preparation of a urethane polyol as claimed in claim 5 or claim 6 which comprises reacting a compound A_n -M wherein M is as defined in claim 5 or claim 6, A is a primary or secondary amine group and n is a number greater than or equal to 2 with ethylene carbonate.